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Nuclear Theory·nucl-th

Wednesday·June 10, 2015

7 papers—3 primary·4 cross-listed

All7Primary3Cross-lists4
  1. 04

    Theory of the n=2 levels in muonic deuterium

    Julian J. Krauth · Marc Diepold · Beatrice Franke · Aldo Antognini · Franz Kottmann · Randolf Pohl

    The present knowledge of Lamb shift, fine- and hyperfine structure of the and states in muonic deuterium is reviewed in anticipation of the results of a first measurement of several transition frequencies in muonic deuterium (). A term-by-term comparison of all available sources reveals reliable values and uncertainties of the QED and nuclear structure-dependent contributions to the Lamb shift, which are essential for a determination of the deuteron rms charge radius from . Apparent discrepancies between different sources are resolved, in particular for the difficult two-photon exchange contributions. Problematic single-sourced terms are identified which require independent recalculation.

    ↳ physics.atom-phnucl-thAnnals Phys.(2016)·76 citations
  2. 05

    Proof of NRQCD Factorization at All Order in Coupling Constant in Heavy Quarkonium Production

    Gouranga C. Nayak🇺🇸

    Recently the proof of factorization in heavy quarkonium production in NRQCD color octet mechanism is given at next-to-next-to-leading order (NNLO) in coupling constant by using diagrammatic method of QCD. In this paper we prove factorization in heavy quarkonium production in NRQCD color octet mechanism at all order in coupling constant by using path integral method of QCD. Our proof is valid to all powers in the heavy quark relative velocity. We find that the gauge invariance and the factorization at all order in coupling constant require gauge-completed non-perturbative NRQCD matrix elements that were introduced previously to prove factorization at NNLO.

    ↳ hep-phhep-latnucl-thEPJC(2016)·37 citations
  3. 06

    Two photon exchange amplitude with \pi N intermediate states: spin-1/2 and spin-3/2 channels

    Dmitry Borisyuk🇺🇦 · Alexander Kobushkin🇺🇦

    We calculate two-photon exchange (TPE) amplitudes for the elastic electron-proton scattering, and take into account intermediate hadronic states containing \pi N system with total angular momentum 1/2 or 3/2, which includes 8 different channels. This is the improvement of our previous calculation, where only the \pi N states with quantum numbers of \Delta(1232) resonance were included. The results show good consistency with recent experimental data. At high Q^2, newly-calculated contributions affect the correction to the measured proton form factor ratio \mu G_E/G_M. The total correction becomes somewhat smaller compared to our previous work, but is still significant and grows approximately linearly with Q^2. Comparing contributions of different channels, we found that larger contributions come from the channels with quantum numbers of lightest resonances.

    ↳ hep-phnucl-exnucl-thPRC(2015)·32 citations
  4. 07

    Generalized perturbations in neutrino mixing

    Jiajun Liao🇺🇸 · D. Marfatia🇺🇸 · K. Whisnant🇺🇸

    We derive expressions for the neutrino mixing parameters that result from complex perturbations on (1) the Majorana neutrino mass matrix (in the basis of charged lepton mass eigenstates) and on (2) the charged lepton mass matrix, for arbitrary initial (unperturbed) mixing matrices. In the first case, we find that the phases of the elements of the perturbation matrix, and the initial values of the Dirac and Majorana phases, strongly impact the leading order corrections to the neutrino mixing parameters and phases. For experimentally compatible scenarios wherein the initial neutrino mass matrix has symmetry, we find that the Dirac phase can take any value under small perturbations. Similarly, in the second case, perturbations to the charged lepton mass matrix can generate large corrections to the mixing angles and phases of the PMNS matrix. As an illustration of our generalized procedure, we apply it to a situation in which nonstandard scalar and nonstandard vector interactions simultaneously affect neutrino oscillations.

    ↳ hep-phhep-exnucl-exnucl-thPRD(2015)·12 citations

Affiliations

first authorsco-authorsvia INSPIRE